Thermostatic switch



Sept. 15, 1931. J E. BRITT 1,823,345

THERMOSTATIG SWITCH Filed July 30, 1927 2 Sheets-5heet l INVENTOR James 5 5/777? A T-ORNEY Sept. 15, 19 31. J. E. BRIII'T 5 THERMOSTATIC SWITCH Filed July 30, 1927 2 Sheets-Sheet. 2

Hy. 6 l3 /7 i /o I T l ,J/ J\ ll 56 37 /a a7 58 INVENTOR James EBr/f/f A dRNEY Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE JAMES E. IBBITT, 0] WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 01 PENNSYL- VANIA TEERMOSTATIG SWITCH Application filed July 30,

My invention relates to thermostatic devices and particularly to thermostatic switches of the quiclr-make-and-break type.

An object of my invention is to provide a thermostatically actuable switch that shall be rigid, compact and simple in construction.

Another object of my invention is to provide for quick break and make of the contacts of a switch structure by causing a snapacting thermostatic member to actuate resilient contact-actuating means.

And a further object of my invention is to provide a thermostatic switch in which positive contact pressure is maintained between the contact members until the instant of disengagement.

In practicing my invention, I provide a switch that comprises, in general, a resilient contact member, a thermostatic snap-acting member, a support for said members and means for causing the snap-acting member to impart a snap movement or motion to the resilient member.

For a fuller understanding of my invention reference may be had to the following description. taken in conjunction with the accompanying drawings, in which,

Figure 1 is a top plan view of one embodiment of my invention.

Fig. 2 is a view, in section, taken on lines II-II of Fig. 1.

Fig. 3 is a bottom plan view of the same device.

Fig. 4 is a view, in front elevation, of the modification of the device embodying my in-' vention.

Fig. 5 is a bottom plan view thereof.

Fig. 6 is a view, in front elevation, of a still further modification of the device embodying my invention, and

Fig. 7 is a bottom planview of the same device- In Figs. 1 to 3 is illustrated a thermostatic be secured 'to the base by a bolt 13 and cooperating nuts 14 to 18, inclusive. The bolt 13 may be insulated from the base by means 1927. Serial No. 208,415.

of washers 19 of insulating material located in recesses 21 and 22 provided in the base.

The base is provided with terminal bolts 24 and 25 that extend therethrough and are insulated therefrom by washers 26 of suitable insulating material located in recesses provided in the top and bottom sides of the base. The terminal bolts may be held securely in place by means of washers 28 and nuts 29. As shown, the heads 31 of the bolts are located on the bottom side of the base and form the stationary contacts for the switch,

the body portion of the bolts extending above the nuts 29 and forming the terminals of the switch.

The resilient disc 11 may be made from a blank ofsuch metal as monel, nickel-steel or other suitable material. The rim of the blank may be rovided with two substantially right-ang e bends 33 and 34 to form a section of substantially L shape (see Fig. 2). As shown, a portion of the rim of the disc extends inwardly towards the bolt 13 from the right-angle bend 34.

The resilient disc may be provided with contact-supporting members 35 and 36 that may be formed b punching and bending in any manner we 1 known in the art. The members 35 and 36 are provided with contact buttons or tips 37 that co-operate with, and normally engage, the stationary contacts 31. In order that the disc or resilient member 11 may cause the contact members 37 to normally engage the stationary contacts 31 and, in order that the member may have two opposed limiting positions, it may be drawn or pressed into a saucer or cup-like structure; that is, the surface from the rightangle bend 33 towards the center of the disc may be made slightly spheroidal, as shown in Fig. 2.

As shown, in Fig. 2 of the drawings, the bimetallic disc 12 is located directly beneath the spheroidal portion of the resilient member 11 and is of such dimensions that the periphery thereof will engage the portion extending inwardly from the right-an 1e bend 34, when the disc 12 is actuated to its opposed limiting position, illustrated by the broken lines of Fig. 2.

I in the patent to Spencer No. 1,448,240 the characteristics of which are such that, when the disc is normally cool, it assumes one lim- I iting position, illustrated by the full-line position of Fig. 2, and anopposed limiting position, illustrated by the broken-line po sition of the same figure when heated to a temperature of a predetermined value.

When the disc 12 is below a predetermined temperature, the resilient member 11 is in the position shown in Fig. 2 of the drawings so that engagement is effected between the contacts 31 and 37. If the disc is heated to a predetermined temperature of a higher value, it will be caused to deflect .to the broken-line position with a snap motion, causing the resilient member 11 to be actuated to its broken-line position by impact between the perilphery of the disc 12 and the portion exten mg inwardly from the right-angle bend 34. Thus, disengagement of the contacts 37 from the co-operating stationary contacts 31 is effected with a positive snap movement.

Since the resilient member 11 is provided with a substantially spheroidal surface, the

member will remain in its broken-line o- -sition, and the contacts will be held in a isengaged or open-circuit position. Re-engagement of the contact members maybe effected when the disc 12 is cooled to the firstnamed temperature, at which temperature the disc will be caused tomake impact with of the thermostatic switch illustrated in silientf contact-actuating member 41, and a Figs. 1 to 3 is shown that comprises a'base 38 having depending lug portions 39 a rethermostatic member 42.

' The resilient member 41 comprises a strip of single-metal material having a deformed middle portion :43 of substantially U-shape.

The resilient member may be provided with contacts 44 and- .45 locatedone on each side of the portion'43. As shown, the member 41 is bowed upwardly so that the contacts 44' and 45 normally engage a pair "of'sta tionary contacts 46 having terminal bolts 47 secured thereto.

insulated therefrom by means of insulating washers. 48 and nuts49.

The thermostatic member 42 comprises a.

strip having a deformed middle portion 51 substantially like the portion 43 of the strip 41 and may bemade from bimetal having suitable thermal expansion characteristics.

The thermostatic member. is supported-by the lug members 39 and is disposed in com- The bolts .47 extend through the base and are secured thereto and be substantially in engagement with each other, if so desired.

In order that the contact members 44 and 45 may be disengaged from the stationary contacts 46, when the thermostatic member 42 has been heated to a temperature'of a predetermined value, a connecting lostmotion link 52 is provided. The connecting link 52 comprises a pin having a body portion and head portions located at each end thereof, the latter being located one on each side of the strips 41 and 42.

When the member 42 has been heated to a temperature of a predetermined value, it is caused to deflect downwardly to the position shown by the broken lines with a snap motion, causing the middle portion 51 to impact with the lowermost head of the link 52, thereby causing the strip 41 to be actuated downwardly with a sudden positive motion to effect disengagement of the contact members. When the strip 42 is cooled to a temperature of a predetermined value, it is caused to deflect upwardly to effect reengagement of the-contact members by impact of the portion 51 with the-portion 43 of the resilient strip 41.

In Figs. 6 and 7 parts similar to those of Fig. 1 are illustrated by like numerals. In these figures, a resilient member 54 comprises a strip of resilient spring steel or other suitable material having end portions 55 and 56 of substantially L-shape. As shown, an enlarged middle portion 55 thereof is secured'to the bolt 13 beneath the thermostatic disc 12. Thestrip may be of such shape that the contact members 37 normally engage the stationary contacts 31.

When the temperature of the thermostatic disc 12 reaches a predetermined value, it dein such direction that'the curvature thereof is reversed, thereby causing the rim portion of the disc to so impact with adjustable lugs 56 secured to the strip 54 that disengagement is efiected between the contacts 37 and 31, substantially in the manner here-,

inbefore set forth for the device illustrated in Figs. 1 to: 3. When the disc 12 has cooled to a temperature of apredetermined value it deflects to the position illustrated in Fig. 6 causing the'upper side of the discto'impact with adjustable lugs 58 that are secured to the strip 54 adjacent tothe contacts 31- and 37. p

By my invention, I have provided a. ther mostatic switch that comprises .a resilient contact-actuating member and a snap-acting thermostatic member forca'using the resilient contact-supporting member to be actuated from one position toanother with a positive snap motion in such' manner that positive engagement and disengagement may be effected between the contacts actuated thereby and cooperating stationary contacts.

-' Various modifications may be made in the desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art'and the appended claims.

I claim as my invention:

1. A thermostatic circuit-controlling device comprising a support, a resilient member carried thereby, contact members carried by said resilient member and thermostatic means having a snap-action motion characteristic for controlling the position of said resilient member.

2. A thermostatic circuit-controlling device comprising a support, a resilient member carried thereby, contact members carried by said resilient member and a thermostatic ele-' ment having'a snap-action motion characteristic carried by said support, and means cooperating with said element and resilient member for causing said resilient member to be actuated with a snap motion from one positionto another.

3. A v thermally-actuable circuit-controlling device comprising a support, a resilient metal member carried thereby, contact members carried by said resilient member, a snapacting bimetallic element carried by said support, said element being adapted to move between two limiting'positions with a snap motion and means for imparting motion to said resilient member from said bimetallic element wherebythe positions of said contact members may be controlled.

4. A thermally-actuable device comprising a support, a snap-acting metal element carried thereby, contact members carried by said element, a snap-acting bimetallic member supported in close proximity to said metal Y element, and means carried by said metal element and located in the path of movement of the bimetallic member for causing movement of said contact members from one position to another in response to impacts between the bimetallic member and said means.

5. A thermostatic switch comprising a metal snap-acting disc, contact members actuable thereby, a snap-acting bimetallic disc and a common support for said' discs, said bimetallic disc being adapted to ,eflect movement of the metal disc by impact therewith.

6. A thermostatic switch comprising a base,

from said base, said member being provided with contact members normally engaging said insulatedly mounted contact members, of a snap-acting bimetallic disc supported r'rom said base for impacting with said resilient memberto efi'ect disengagement of said contact members with a snap motion when one temperature obtains in the said disc and for reengaging said contact members when another temperature obtains therein.

8. A quick make-and-break switch comprising a support, contact members secured to said support, a primary snap-acting thermostatic element carried by said support, a secondary snap-acting. element, contact members carried thereby for cooperating with said first named contact members, said thermostatic element being adapted to actuate said secondary element from one position to another with a sudden snap motion.

9. A quick make-and-break switch comprising a support, a primary thermostatic element capable of assuming either one of two extreme stable positions in response to predetermined thermal conditions, means for securing said element to said support and a secondary element adapted to assume either one of two extreme stable positions, said primary element being operable to actuate said secondary element from one stable position to another.

10. In a thermostatic switch, a primary snapping element thermally actuated, a secondary snapping element adapted to be actuated by said thermally actuated rima element, contact members carried y sai secondary element, a support for said snapping elements, and contact members carried by the support for cooperating with said first named contact members secured thereto, a resilient member supported from said base, said member having contact members thereon normally engaging said first named contacts and a snapacting bimetallic disc located in close proximity to said resilient member for causing movement thereof by impact therewith, whereby disengagement of said contact members may be effected with a snap motion.

7. The combination with a base, contact members insulatedly mounted thereon and a resilient snap-acting metal member supported 

